A RETIRED mathematician who walked into the Houses of Parliament with an air pistol and a knife in his bag has been spared a jail term.

Paul Benson, 62, from Croydon Road in Caterham, pleaded guilty last Monday (December 3) to possessing an imitation firearm in a public place and possessing a blade in a public place - but Southwark Crown Court heard he had the items because he was from the "boy scout generation".

Benson, who has to walk with a cane, was due to meet his local MP, Sam Gyimah, on November 3 last year to argue the case for protestors from the Occupy group who were camped outside St Paul's Cathedral last year.

But the weapons were discovered when he tried to go through security at the public entrance to the Palace of Westminster, the court heard.

"A security officer began to search the rucksack Mr Benson had with him, and noticed a dense and heavy item in the bag," said prosecutor Peter Zinner.

"She asked if he had any electrical items or dense items, and he replied 'Yeah, I have a gun'.

"This was during a sensitive time when everyone is very security conscious, so this caused a great deal of alarm."

The court heard the entrance was shut down and specialist firearms officers were sent to the scene when an AirSoft pistol wrapped in a pink cloth was discovered in Benson's bag.

"It is described as a true replica of a handgun pistol," Mr Zinner explained.

"It was not dangerous and couldn't have caused any real harm, but it caused a great deal of alarm in all the circumstances."

Benson was asked whether he was carrying anything else, and he promptly took out a retractable Stanley knife which was pinned to his jumper, the court was told.

Barry Gregory, defending, said: "He simply had the retractable blade knife for the purpose of whittling wood and sharpening pencils, nothing of great note.

"With regard to the imitation firearm, directly there was a challenge and he said 'Oh yes, there's a gun in the bag'.

"He used it in the woods for target practice, and had no intention of taking that with him.

"It never occurred to him such things were weapons and would ever be used on anyone else.

"My client is of the generation of the boy scout who were told it's a good idea to carry a knife and a piece of string and other such things."

Benson, who was diagnosed with bi-polar affective disorder in April this year, was detained under the Mental Health Act in Crawley's Langley Green Hospital for two months following the incident, after suffering from what was believed to have been a "manic episode".

Mr Gregory added that his client had promised not to carry a knife anymore and did not intend to replace the air pistol.

Judge Jeffrey Pegden QC sentenced Benson to nine months in jail, suspended for 18 months, and gave him an 18-month supervision order.

The judge said: "It is important to note the prosecution do not attribute any sinister purpose for having the weapons with you when you visited the Houses of Parliament.